
TACHINIDAE OF AUSTRALIA 13 
taxonomic importance at several levels in different parts of the family. Often 
the depression extends backwards to reach the end of the segment, in which 
case T1 + 2 is described as ‘excavate to its hind margin’, but in many forms 
the depression clearly falls short of the hind margin or there is virtually no 
depression at all (e.g. many Phasiinae, Doleschallini). When Tr + 2 is excavate 
to its hind margin this condition often holds true of all the members of a tribe 
(e.g. all Rutiliini, all Sturmiini); in other tribes (e.g. Blondeliini) the tergite 
may be excavate to its hind margin in some genera but not others. In many 
Prosenini the excavation is rather deep and narrow and the sides of Tr + 2 
are rather strongly humped. 
face. The anteromedian surface of the head below the antennae and between the 
facial ridges (clypeus of Townsend) (Text-fig. 2). 
facial carina. A strong median vertical ridge on the face separating the antennae 
(facial keel) (Text-fig. 12). 
The presence or absence of a facial carina, and its form when present, provide 
important key characters for recognition of some forms. In most Tachinidae 
the face is flat or only weakly raised medially, but a large facial carina is present 
in many Proseninae (Prosena, Senostoma, Billaea and all Rutiliini). When a 
carina is present it is typically flattened or convex on its anterior surface, or 
prominently bulbous on its upper part and contracting to a sharper ridge 
towards the lower end, but a sharp roof-like carina occurs in Euthera. <A true 
facial carina is absent in Tachininae and Goniinae, but a weak swelling may be 
present below and between the antennal bases (e.g. in Macrochloria). 
facial profile. The anterior outline of the head between the antennal base and 
the epistome when viewed in profile. 
facial region. The face, facial ridges and parafacials collectively. 
facial ridges. The flattened or raised strips differentiated on each side of the 
face that separate it from the parafacials (facialia) (Text-fig. 2). 
These are of great importance in taxonomy because of their variously modified 
form (whether ridge-like lateral margins to the sunken face or flattened and 
in the plane of the face), the extent of their visibility when the head is viewed 
in profile, and the extent to which they bear hair or setae. In many aberrant 
forms (e.g. Therobia, Myiotrixa) they are widened and flattened ventrally and 
extensively haired, but typically they are at least slightly ridge-like and have 
at least a few setulae immediately above the vibrissae (which in normal forms 
demarcate the ventral ends of the ridges); in many genera of Tachininae and 
Goniinae the ridges bear strong downcurved setae or setulae on most of their 
height. 
fascia. A transverse band on the dorsum of thorax or abdomen. 
frons. The anterodorsal region of the head bounded by the eyes laterally and 
extending from the ocellar triangle to the lunula; the interfrontal area and the 
parafrontals collectively. 
Typically the frons is well developed in both sexes, though usually narrower 
in the male than the female, but is strongly reduced in some forms in which the 
head is holoptic or almost so (e.g. in males of many Formosia, Ormiini and 
